Distributed network register

ABSTRACT

The invention relates to a method for operating a telecommunications network and a telecommunications network for mobile telecommunication, having a network register in which identifier of mobile terminals and network-related user data of the terminals are stored. The network register is formed from a peer-to-peer network having a multiplicity of decentralized register nodes which are networked with one another and are each associated with a geographic region. Hash tables are held in the register nodes, in which hash tables the identifiers of the terminals are stored as hash values and the user data is stored associated with these hash values. The network has at least a first node associated with a geographic region at which a terminal can register, and a second node, which is permanently assigned to the terminal and is associated with a geographic region. The terminal registers with the first node by transmitting the identifier, when it is located in the first region. The first node then determines network-related user data of the mobile terminal on registration, and determines the hash value for that identifier. This hash value is used to determine the second node. The first node either transmits the network-related user data to this second node or itself stores this user data in his hash table together with the hash value and transmits only its own address in the network to the second node. Either the network-related user data or the address of the first node is then stored, associated with the hash value, in the hash table of the second node.

The present invention relates to a method for operating atelecommunications network for mobile telecommunication, having anetwork register in which identifiers of mobile terminals andnetwork-related user data of the terminals are stored, wherein thenetwork register is formed from a peer-to-peer network having amultiplicity of decentralized register nodes which are networked withone another and are each associated with a geographic region, andwherein hash tables are held in the register nodes in which hash tablesthe identifiers of the terminals are stored as hash values and the userdata is stored associated with these hash values. The inventionfurthermore relates to a telecommunications network for carrying out themethod.

For operation of a mobile radio network it is known to use a so-calledhome location register (HLR) in order to reach and to localize theterminals of mobile radio subscribers in the mobile radio network. Thehome location register is a central database, which is an essentialcomponent of a mobile radio network. The mobile radio terminals arestored with the associated phone numbers (MSISDN, mobile subscriberISDN), their status, that is to say whether or not they are registeredin the mobile radio network, and their current location. In order to setup a communication link between a first mobile radio terminal and asecond mobile radio terminal, the home location register is first of allchecked to determine whether the second mobile radio terminal isregistered in the mobile radio network. If this is the case, theregister determines the cell in which the subscriber to be called islocated, that is to say where it is registered, and the call is routedto the respective radio cell of the mobile radio network. The terminalis then reached, and can accept the call.

This technology, which is currently used by the mobile radio operators,leads to an extremely large central database, which manages thenetwork-related user data of all subscribers in the mobiletelecommunications network. This database is associated with a temporarybuffer store, the so-called visitor location register (VLR), which islocated in a mobile switching center (MSC) of a cell, and in which userdata are stored for those mobile radio terminals which are currentlylocated in the geographic coverage area of that switching center. Thehome location register and the visitor location register furthermorecontain user's main data, by means of which authorization isverifications can be obtained for authentication purposes. Furtherinformation relating to the home location register and the visitorlocation register is defined in international Standards, as specified bythe European Telecommunications Standards Institute (ETSI) or the 3rdGeneration Partnership Project (3GPP).

The so-called home subscriber service (HSS) represents a furtherdevelopment of the home location register (HLR). This is a databasewhich is used for authentication and authorization of users within theso-called IP multimedia subsystem (IMS). The IMS is a collection ofspecifications of the 3GPP, with the purpose of standardizing access toservices based on different network technologies. The home subscriberserver therefore provides similar functions as the home locationregister, although these functions have been developed specifically forInternet-protocol (IP)-based networks. The home subscriber servercomprises user data such as user profiles, data for user authenticationand data relating to the location of the user within the network. Thehome subscriber server is also implemented as a central entity with alarge database in the network.

The disadvantage of such central databases is obvious. On one hand, anenormous size is required for the databases, in order to store the userdata of all network subscribers. This results in high hardware costs andconsiderable technical complexity, in order to provide the memorycapacity and the high data transfer rate for simultaneous access to aplurality of user data items in the database. On the other hand, acentral database involves a considerable failure risk, with thecommunication throughout the entire network collapsing if the databasefails.

In the field of wired IP (Internet Protocol)-based networks, so-calledpeer-to-peer networks are known, in which all the network nodes haveequal authority and are connected to one another, and in which data isstored in a correspondingly decentralized form, distributed across thenetwork. Central entities such as databases for storage of user data canbe saved in this way. When using this technology, the user data isstored in the terminals which are used for communication, that is to saythe computers which are connected to the network.

So-called distributed hash tables are used to store and find data. Theseare used to find data elements in a large data set, by providing anindex structure in the form of a table. Distributed hash tables (DHT)make it possible to distribute data objects as uniformly as possibleacross all the nodes, allowing routing to a specific network node,independently of the location of a certain entry point.

Consistent hash functions form the basis of distributed hash tables andare used to allocate keys in a linear value range to the data objects.In this case, the value range is distributed as uniformly as possiblebetween the network nodes of the node quantity, with each node beingresponsible for at least one subspace of the key space. In the hashtables, information is stored in the form of a data pair comprising thekey, also referred to as the hash value, and information associated withit. When a search is carried out for a specific data object in apeer-to-peer network, this can be done by means of distributed hashtables such that the hash function is used to calculate a hash value forthe name (identifier) which identifies the data object, which hash valuecontains the memory location of the data object in the network, thusmaking it possible to search for the data object at the correctlocation. With the name converted to a hash value, distributed hashtables represent an efficient mechanism for storage and finding ofinformation items associated with the hash value.

The object of the present invention is to provide a method for operatinga telecommunications network for mobile telecommunication, and toprovide a corresponding telecommunications network which offers a highdegree of fail-safety with reduced costs and less technical complexityfor the storage of network-related user data in a network register whichmanages such data.

This object is achieved by the features of independent claims 1 and 7.Advantageous developments of the method and of the system are formulatedin the dependent claims, and will be explained in the following text.

According to the invention, a method is proposed for operating atelecommunications network for mobile telecommunication, having anetwork register in which identifiers of mobile terminals forcommunication via the telecommunications network and network-relateduser data of the terminals are stored, wherein the network register isformed from a peer-to-peer network having a multiplicity ofdecentralized register nodes which are networked with one another andare each associated with one geographic region, wherein hash tables areheld in the register nodes, in which hash tables the identifiers of theterminals are stored as hash values, and user data is stored associatedwith these hash values.

This results in a distributed network register, referred to in thefollowing text as a DNR (Distributed Network Registry), which is formedfrom a distributed database, with each register node holding andmanaging a part of the database content and thus participating in thedistributed network register. In this case, the concept of thedistributed network register comprises two main functions, specificallythe storage of user-related network data in a memory device, and thefinding and provision of this user data which are stored in a databaseof a register node. These two functions are independent of one another,and may be realized in different forms.

The information, that is to say the network-related user data, which isprovided in the distributed network register can be used for variouspurposes, for example for localization of a network subscriber in orderto set up a voice communication, for preparation for a media change,also referred to as a handover from one network technology to another,for preparing of a media change from one antenna to another, or fornegotiating a coding to be used in conjunction with the specificcharacteristics of the network, that is to say in conjunction with theavailable bandwidth, delay times and jitter that occurs.

The user data comprise information which relates to an individualnetwork user within a specific geographic region of thetelecommunications network of a telecommunications network operator. Byway of example, data such as this may be:

-   -   registration status of the user and information as to where the        currently assumed location of the user or his mobile terminal        is, that is to say where this was most recently “seen” in the        network; by way of example, this may be identifier of a base        station responsible for a specific mobile radio cell;    -   available network technologies which provide network coverage        and therefore reachability of the user in the region in which        the user is currently located, and which provide access to the        telecommunications network operated by the mobile radio        operator;    -   the quality of the various networks and network technologies        which, in the vicinity of the user, ensure appropriate access to        the network of the mobile radio operator;    -   the IP address of the user and/or other identifiers of the user        like MSISDN or IMSI, or else other usable information for        access-specific authentication processes;    -   materials for access-specific authentication processes or, if        necessary, materials for central access with the collaboration        of a plurality of users from different access locations.

These types of information are updated continuously soon as a user moveswithin the network. The updated information represents newcharacteristics which are or can be associated with the user, forexample where he was most recently seen within the network, when he waslast seen, network coverage aspects, or when the user has moved withinthe network.

User-related data which are stored in the distributed network registercan be localized by using a hash function to convert an identifierassociated with the user to a hash value. This so-called “hashed”identity of the user can be used as a key is word for a search at anynetwork node which is participating in the distributed network register,in order to find that register node which is responsible for the storageof the network-related user information. One hash function which can beused for DRN is the so-called SHA-1 algorithm (SHA, secure hashalgorithm). When using the SHA-1 algorithm, the “hashed” identity isgenerated either from the MSISDN (mobile subscriber ISDN number) or analternative identifier such as an e-mail address or a SIP (sessioninitiation protocol) identifier, and the “hashed” identifiers determinedby the hash function are distributed uniformly over the entire possiblespace. However, it would also be possible to use a different algorithm.As soon as this register node which is responsible for the storage ofthe network-related user data has been found in the distributed networkregister, this node can be searched by using the hash value, in order tofind the information held in this registry node associated to this hashvalue or to the user respectively.

According to the invention, the distributed network register may be acomponent of a mobile radio network, with the mobile terminals beingformed by mobile terminals which can communicate via the mobile radionetwork with one another and with external terminals, such as fixed linetelephones. For the purposes of the invention, the identifier of aterminal may be any desired numeric or alphanumeric character sequencewhich uniquely identifies the terminal in the telecommunicationsnetwork. The identifier is preferably the MSISDN (mobile subscriber ISDNnumber) associated with a mobile radio terminal. Alternatively, theidentifier may be an e-mail address, a SIP address (session initiationprotocol), an IP-Address, an IMSI (International Mobile SubscriberIdentity) or any other unique identifier.

According to the invention, the decentralized network register is formedby a peer-to-peer network having a multiplicity of decentralizedregister nodes which are networked with one another and are eachassociated with one geographic region. By way of example, in the case ofcellular mobile radio networks, a geographic region such as this may beone or more mobile radio network cell/cells, that is to say a boundedgeographic area in which one or more network node/nodes provide/providesa network access point to the network, in particular the mobile radionetwork. A network access point such as this may be provided by a basestation in a GSM/GPRS mobile radio network (Global System for MobileCommunication, General Packet Radio Service), a UMTS mobile radionetwork (Universal Mobile Telecommunications System), a WLAN router(Wireless Local Area Network) or a cable-based access network such asDSL (Digital Subscriber line), ISDN, glass fiber or television cable.Because of the locally restricted transmission and reception range ofthese network access points, there are restricted geographic regionsassociated with these kind of network nodes.

In order to form the distributed network register, the register nodescontain hash tables in which the identifiers of the terminals, forexample the phone numbers of the mobile radio terminal devices arestored as hash values calculated by means of a predetermined hashfunction, and the network-related user data are stored, associated withthese hash values, in the hash table. A hash value uniquely identifies aterminal used in the telecommunications network, on the one hand, aswell as a specific memory location for the associated user data withinthe is decentralized network register, on the other hand, as a result ofwhich this user data can be found by means of the hash value in thenetwork register.

The network has at least one first register node which is associatedwith a geographic region in which a mobile terminal can register forcommunication via the telecommunications network, and a second registernode, which is permanently assigned to the terminal and is associatedwith a different geographic region. The first node may be any desiredregister node in the network, that is to say located anywhere, via whichthe terminal can access the network. It is not a specific node in thenetwork. In fact, a register node with which the terminal registers inthe network is actually the first register node in the meaning of theinvention. In contrast, the second register node is always the samenode. Consequently, the second register node always remains the samewithin the network and is permanently associated with a specificterminal. It should be noted that the first register node may be formedby the second register node. This is the case when the terminal islocated in that region which is associated with the second register nodebeing assigned permanently to the terminal.

By way of example, the assignment may be realized at the same time asthe allocation of the identifier to the device or to a subscriber. Inthis case, the association is carried out such that the second registernode, or its address within the network, is uniquely evident from thehash value of the identifier of the terminal. By way of example, thisassociation can be achieved by that the last three digits of the hashvalue indicate to the register node which is permanently assigned to theterminal. This can result in a maximum of 1000 uniquely identifiableregister nodes, which form the distributed network register and betweenwhich all of the user data of terminals which communicate via thetelecommunications network are distributed.

For data storage within the decentralized network register, a hash tablecan first of all be created and held in the second register node, inwhich hash table the identifier associated with the terminal is storedas a hash value determined by means of a predetermined hash function. Ifthe terminal is located within the geographic region associated with thefirst register node, it registers with this register node bytransmitting its identifier, and the register node determinesnetwork-related user data of the mobile terminal on registration anddetermines a hash value for the identifier by means of the predeterminedhash function. The first register node can then use the hash value todetermine the second register node and either transmits thenetwork-related user data to this second register node or itself storesthis user data in his hash table together with the hash value, andtransmit only its own address in the peer-to-network in the secondregister node, so that the register node which is permanently assignedto the terminal contains only a pointer to that register node whichcurrently holds the user data due to the fact the terminal has currentlyregistered at this register node. The second register node thenassociates the transmitted network-related data or the transmittedaddress of the first register node with the hash value in its hashtable, and stores this, so that the user data can be found when a searchis requested within the network register.

A request of a system for the current network-related user data of theterminal can be made to a third register node by transmitting theidentifier associated with this terminal. A request such as this may,for example, may be a call from another telecommunication subscriber whoor a terminal which wishes to reach that terminal. The system may be aswitching center via which the call is switched. Alternatively, therequesting system may be a mobile radio terminal. If the system isresident in the same network as the terminal to be reached, this can bereferred to as an internal request. If the requesting system is, incontrast, is a system resident in a different network, that is to say asystem which is not resident in the same network as the called terminal,for example a landline telephone or a switching center which wishes toset up a call to the terminal originating from a foreigntelecommunications network, then this can be referred to as an externalrequest.

The internal or external request can in principle be made to anyregister node in the network. However, in the case of an externalrequest, this register node is preferably a node which is not associatedwith any geographic region, but in fact is arranged in the peer-to-peernetwork without any such association. Furthermore, in the case of aninternal request, the register node is that register node which isassociated with that region within which the requesting system, i.e. therequesting mobile radio terminal is located and is provided access tothe network. This means that the third register node may be any registernode in the network, and in particular may be identical to the first orthe second register node. The expression used here as “third registernode” is only for linguistic distinction.

When the identifier associated with the terminal to be reached istransmitted to the third register node, the latter can determine thehash value of the identifier by means of the predetermined hashfunction, and can determine the second register node assigned to theterminal, from the hash value. It can then check the informationassociated with this hash value in the hash table of the second registernode by transmitting the hash value to the second register node andrequesting the information stored in association to this hash value inthe second node. The information stored in association to this hashvalue can be user data or the address of the first register node whichholds these user data. By this, it can obtain the information as towhether the called terminal is currently registered in thetelecommunications network and, if it is registered, can obtain theinformation as to the region, in particular the mobile radio cell, inwhich the terminal is currently located. Alternatively, the thirdregister node can transmit the identifier directly to the secondregister node, which then itself determines the hash value.

If the information stored in the second register node relating to thehash value is network-related user data, this data can be transmitted tothe requesting system, thus allowing a communication link to be set upfrom the system to the terminal to be called. If the informationassociated with the hash value in the second register node is, in analternative embodiment an address of a further register node whichcontains the requested network-related user data, it is possible tocheck the user data in this register node.

If the terminal has most recently registered with the first registernode, its address is correspondingly stored, associated with the hashvalue, in the hash table of the second register node. The secondregister node can then transmit the address of the first register nodeto the third register node, which then checks the user data in the firstregister node. This can be done by the third register node transmittingthe identifier of the terminal, or straight away transmitting the hashvalue of the identifier to the first register node, as a result of whichthis first register node can find in its hash table the table entrywhich is correspondingly associated with this hash value, that is to saythe network-related user data of the terminal. If only the identifier ofthe terminal is transmitted to the first register node, the firstregister node calculates the hash value of the identifier itself. Thenetwork-related user data is then transmitted to the third registernode, which passes this on to the requesting system. In an alternativeembodiment the second register node can forward the request of the thirdregister node to the first register node which in return transmits thenetwork-related user data back to the second or directly to the thirdregister node. The latter would require the second node to provide theaddress of the third node to the first node. If the terminal moves outof the region associated with the first register node into anotherregion for which a different register node is responsible, the terminalcorrespondingly registers with this register node by transmitting theidentifier. On registration, this register node then determines currentnetwork-related user data of the mobile terminal and determines a hashvalue for identifier, in accordance with the predetermined hashfunction. This new register node can then store the specific hash valuetogether with the current network-related user data in a hash table heldin it, uses the hash value to determine the second register node whichis assigned to the terminal, and can transmit to this second registernode its address, which then stores the address of the new registernode, associated with the hash value, in its hash table. Alternatively,the new register node uses the hash value to determine the secondregister node which is assigned to the terminal, and transmits all thenetwork-related user data to this second register node, which thenstores the user data, associated with the hash value, in its hash table.

In the case of the first embodiment, the new register node has all thenetwork-related user information of the terminal while, in contrast, inthe second embodiment, the register node which is permanently assignedto the terminal has all the network-related user data. As, in the secondembodiment, one and the same register node always holds the current userdata, this procedure can be referred to as a static usage scheme. As, inthe first embodiment, a different register node is responsible for themanagement of the network-related user data, changing depending on thegeographic region, this procedure can be considered to be a dynamicusage scheme.

According to the invention, the network-specific user data preferablycomprises the registration state of the terminal, its location in ageographic region, and/or information relating to the availability ofaccess networks to the telecommunications network within the region,that is to say information such as network coverage, network strength oravailable network technology in the vicinity of the terminal.

The telecommunications network according to the invention for mobiletelecommunication for carrying out the specified method has a networkregister in which user data for the terminals, relating to identifiersof mobile terminals for communication via the telecommunications networkare stored, wherein the network register is in the form of apeer-to-peer network with a multiplicity of decentralized register nodeswhich are networked with one another and are each associated with onegeographic region, wherein hash tables are held in the register nodes,in which hash tables the identifiers of the terminals can be stored ashash values, and the user data is stored associated with these hashvalues. The telecommunications network for carrying out the methodcomprises at least one first register node which is associated with ageographic region and with which a mobile terminal can register forcommunication via the network, and a second register node, which ispermanently assigned to the terminal and is associated with a differentgeographic region, wherein a hash table is held in the second registernode, in which hash table an identifier associated with the terminal isstored as a hash value determined by means of a predetermined hashfunction, the first register node is designed such that the terminal canregister with it by transmitting the identifier, when it is located inthe first region, and the first register node is configured to determinenetwork-related user data of the mobile terminal on registration, and todetermine a hash value of the identifier by means of the predeterminedhash function, to determine the second register node from the hash valueand either to transmit the network-related user data to this secondregister node, or to store this user data itself in its hash tabletogether with the hash value, and to transmit only its own address inthe network to the second register node, and wherein the second registernode is configured to store the network-related data or the address ofthe first register node, associated with the hash value, in its hashtable.

A register node may be formed either by a data node or by a localizationnode, or by a node combined form data node and localization node. Theembodiment of the register node as a data node on the one hand and alocalization node on the other hand has the advantage that these nodescan be specialized for specific tasks. In contrast, combined nodes havethe advantage that they act technically in the same way and with thesame function from a network's point of view, thus simplifying thecomplexity of the technical implementation of the method and the DNRaccording to the invention in the peer-to-peer network set up for thispurpose.

Preferably, each region covered by the network can be associated eitherwith a data node and a localization node, or alternatively with acombined node. The network register may accordingly either consistexclusively of combined nodes, exclusively data nodes and localizationnodes, or alternatively may also be implemented using a heterogeneousstructure, that is to say using a structure in which one region or aplurality of regions is or are in each case associated with one combinednode, and the other region or regions is or are in each case associatedwith data nodes and localization nodes. A data node is distinguished inthat the user data which is associated with a terminal is stored in saiddata node, with this storage being carried out associated with the hashvalue of the identifier of this terminal. Furthermore, a localizationnode is distinguished in that it does not manage any user data but infact contains the address, associated with a hash value, of that datanode which is managing the user data associated with the hash value.

The register nodes may be provided as autonomous devices within thenetwork. However, alternatively, they may be arranged within networkelements in the network, such as a base station, an antenna controller,a WLAN router or other servers or gateways of the network operator.

In order to accept requests for the current network-related user data, aspecific register node or all of the register nodes in the network canbe designed to receive a request of a system for the user data of aspecific terminal, and to carry out a search for this user data withinthe network, using the method steps described above.

Further features and advantages of the method according to the inventionand of the network according to the invention will be explained in moredetail in the following text using exemplary embodiments and withreference to the attached figures, in which:

FIG. 1: shows a schematic illustration of the interaction of theindividual network components in a static usage scheme, and

FIG. 2: shows a schematic illustration of the interaction of theindividual network components in a dynamic usage scheme.

FIG. 1 shows a schematic illustration of a telecommunications network Thaving a peer-to-peer network N according to the invention, in which adecentralized network register DNR (distributed network register) isformed by a plurality of register nodes CDNR (combined distributednetwork registry), which are formed from a combination of data nodesDNDR (distributed network data registry) and localization nodes DNLR(distributed network location registries), compare FIG. 2.

By way of example, FIGS. 1 and 2 show five regions A, B, C, D, E, eachof which is associated with a register node CDNR, CDNR1, CDNR2. Itshould be noted that, merely by way of example, FIGS. 1 and 2 show onlyfive regions A, B, C, D, E, while considerably more regions may exist inan actual telecommunications network T.

The register nodes CDNR, CDNR1, CDNR2 are technically equivalent andhave the same function. They are connected to the network N and areconnected to one another, as a result of which the network N representsa peer-to-peer network. The geographic region A, B, C, D, E associatedwith a register node is defined by the reception range of an accesspoint NA, NB, NC to the telecommunications network T. The geographicdimensions of a region A, B, C, D, E may differ depending on theavailable access point or points. The access points NA, NB, NC formaccesses to networks with different technologies, which are operatedjointly by one telecommunications network operator. By way of example, afirst network may be a GSM/GPRS mobile radio network, with the accesspoints NA to this network being formed by base stations the coveragearea of which form the cells of this GSM/GPRS mobile radio network. Byway of example, a second network may be a mobile radio network of theUMTS Standard, with the corresponding access points NB being formed bybase stations which cover the cells of this UMTS mobile radio network.Furthermore, a third network may be formed by an Ethernet, an accesspoint NC to this network being a WLAN router, for example. Othercable-based transmission media may also be used as alternatives, such asDSL, ISDN, glass-fiber cable or television cable. Each of the accesspoints NA, NB, NC using different network technologies, mentioned forillustrative purposes, is a part of the telecommunications is networkoperated or contracted by the telecommunications network operator, andin order to set up communication links to terminals for the userinformation stored in the register nodes CDNR, CDNR1, CDNR2. Furtherwireless network technologies, which can be used to set up access pointsto the telecommunications network T, may be for example CDMA2000 (CodeDivision Multiple Access), LTE (Long Term Evolution), or WiMAX(Worldwide Interoperability for Microwave Access). The accesses NA, NB,NC relate to networks using different technologies, which can be used bythe operator of the telecommunications network T. These accesses NA, NB,NC may be provided in one or more or all the regions A, B, C, D, E ofthe telecommunications network. The register nodes CDNR, CDNR1, CDNR2associated with one region contain databases for storage of thenetwork-related user data of the mobile terminals. Hash tables, in whichdata in the form of a data pair is stored, are set up in the databases.The first element of the data pair is in each case a hash value which isformed in accordance with a predetermined hash function from anidentifier associated with a specific terminal, that is to say forexample from the call number of a mobile radio. The second element ofthe data pair may either be a data object with the network-related userdata or an address of another register node, in which the user data isstored, depending on whether a static or dynamic usage scheme is usedfor carrying out the method according to the invention. This will alsobe illustrated in the following text. In comparison to FIG. 1, FIG. 2shows one embodiment variant of the network according to the inventionwith specific data and location register nodes DNDR, DNLR. In thisembodiment, each region A, B, C, D, E is associated with a data nodeDNDR, DNDR 1, DNDR 2 on the one hand and with a localization node DNLR,DNLR 1 on the other hand. These register nodes also are networked withone another and form a peer-to-peer network N, in which a distributednetwork register DNR is implemented.

A data node DNDR, DNDR 1, DNDR 2 is an element of the distributednetwork register DNR, which is responsible for the storage ofinformation relating to a specific user. User kind of data comprise, forexample, the registration status of a terminal and the current or mostrecent location of a terminal, preferably also information as to whichnetwork technologies NA, NB, NC are in principle and in fact availablein the vicinity of the terminal, and preferably in what network quality.

A localization node DNLR, DNLR1, DNLR2 is also an element of thedistributed network register DNR. It is used to determine the current ormost recent location of a terminal UE within the network. A localizationnode DNLR, DNLR1, DNLR2 can carry out two functions. According to afirst function, it is able to receive a request EQ, IQ fornetwork-related user data, to carry out a search for this user datawithin the network, and to provide the requested user data. According toa second function, a localization node DNLR, DNLR 1 may also be able tostore the address of a data node DNDR, DNDR1, DNDR2 within which, inturn, the network-related user data is stored. It should be noted thatthe localization nodes DNLR need not necessarily all have a storagecapability such as this. In this case, the functionality of alocalization node DNLR is reduced to the first function. By way ofexample, a localization node DNLR2 such as this may be set up withoutbeing associated with a geographic region A, B, C, D, E in the networkN, which node is responsible for receiving external requests EQ for userdata, searching for this user data, and correspondingly providing it.

The user information which is stored in the data nodes DNDR, DNDR1,DNDR2 and the localization nodes DNLR, DNLR1 is stored using distributedhash tables. This user data is stored in a localization node DNLR, DNLR1in the form of a data pair <hash value of the identifier; address of thedata node>. In contrast, the user data is stored in the data nodes DNDR,DNDR1, DNDR2 in the form of a data pair <hash value of the identifier;user data>. The user data is likewise stored in the combined nodes CDNR,CDNR1, CDNR2 in the form of a data pair <hash value of the identifier;user data>. By way of example, a call number in accordance with theE.164 Standard, a SIP address and/or an e-mail address, which uniquelyidentifies a mobile terminal, may be used as an identifier. The hashvalue, also referred to as “hashed identity” or “hashed identifier” isin contrast a numeric or alphanumeric character string which is derivedfrom the identifier using a hash function. The length and the format ofthe identifier are normalized by means of the hash function.

The network register DNR according to the invention may be used in twodifferent embodiment variants, a static usage scheme and a dynamic usagescheme. According to the static usage scheme, all the register nodes ofthe network register can store network-related user data. In thisembodiment, the register nodes are always in the form of combined nodes,that is to say those network nodes which have the functionality of adata node and of a localization node. Furthermore, in this staticembodiment of the method according to the invention, the data node whichmanages specific user data is the same node as the localization node forthis user. The static embodiment can accordingly be implemented usingthe telecommunications network T shown in FIG. 1.

In the alternative dynamic embodiment, which is not shown, some registernodes may only be in the form of localization nodes DNLR, others only inthe form of data nodes DNDR, and in turn others in the form of combinednodes CDNR. In this embodiment, a data node DNDR which contains specificuser data need not necessarily be identical to that data node DNDR whichis assigned to the user.

By way of example, in FIG. 2, a first register node is a data node DNDR1with which a terminal UE is registered for the time for which it remainswithin the region B. On registration, network-related user data isstored in this data node DNDR1. In contrast, one register node ispermanently assigned to the terminal UE as a localization node DNLR1,and is responsible for localization of the terminal UE and forlocalization of the user data associated with the terminal UE. In FIG.2, this localization node DNLR1 is associated with the region D. Theregister node DNLR1 which is responsible for the localization ofterminal UE and the register node DNDR1 managing the current user datafor the terminal UE are in this case not the same node while, incontrast, in the case of the static embodiment shown in FIG. 1, one andthe same register node CDNR2 of the region D is responsible for thelocalization of terminal UE and for the storage and management of itsuser data.

The reference symbols EQ and IQ relate to systems which make a requestfor user-specific information. A system such as this may, for example,be a switching center which receives a call to a terminal UE which isresident in the telecommunications network T. External request EQrelates to a request from a system which is outside thetelecommunications network T and makes use of the decentralized registernode in the distributed network register to obtain user-specific networkdata. In contrast, an internal check IQ means a request from a systemwhich is located within the telecommunications network T and likewisemakes use of the decentralized register node in the distributed networkregister in order to gain access to user-specific network data.

The method steps for management of the decentralized network registerDNR according to the invention will be described in the following textboth for the static embodiment variant and for the dynamic embodimentvariant:

Static usage scheme:

The procedure for operating the network register according to theinvention will be explained on the basis of the arrows in FIG. 1,provided with reference symbols. As soon as a user of thetelecommunications network T activates his mobile terminal UE, it isregistered within the telecommunications network T. This is indicated bythe arrow 0 in FIG. 1, in which case the user is currently located inregion B and registers with the combined register node CDNR1 which isresponsible for this region. On registration, the terminal UE transmitsits identifier via network access point NC of region B to the combinedregister node CDNR1. The register node CDNR1 identifies a new mobileterminal UE and determines a hash value for the identifier associatedwith this terminal UE. Furthermore, the register node CDNR1 identifiesthat register node CDNR2 is responsible for the storage of thenetwork-related user data, and provides to this register node CDNR2 theinformation obtained during registration of the terminal, in particularregistration status and registration location. This process of passinginformation is indicated by the arrow 1. In the illustrated case, thecombined register node CDNR2 of the region D is assigned to the terminalUE and is responsible for the storage of information of the terminal UE.After registration, the combined register node CDNR2 of the region D,which is responsible for the terminal UE, has all the user-specificinformation, such as registration status, location, the networkavailability and network coverage in the immediate vicinity of theterminal UE.

If an internal or external system makes a corresponding internal requestIQ or external request EQ for user data of a specific user with aspecific identifier, this system sends a corresponding request togetherwith this identifier to a combined register node CDNR3. This registernode CDNR3 is not associated with any geographic region. The externalrequest EQ is indicated by the arrow 2 in FIG. 1, the internal requestIQ with the arrow 2 a. The combined register node CNDR3 receives therequest and uses the identifier of the user terminal to calculate a hashvalue. As soon as this hash value has been determined, the requestingregister node CDNR3 sends a request for the specific user data to theappropriate combined register node CDNR2, as is illustrated by the arrow3. The information which register node is responsible for the managementof the specific user data for the terminal UE is determined by therequesting register node CDNR3 from the calculated hash value. Thecombined register node CDNR2 which is responsible for the terminal UEthen sends the requested user data to the requesting register nodeCDNR3, as illustrated by the arrow 4. By this, register node CDNR3receives the information that the terminal UE is registered and can bereached in region B via register node CDNR1. The register node CDNR3 canthen set up a call or send a message to the terminal UE in region B.

When the user moves with his terminal UE from the region B into anotherregion A, it is necessary to update his location in the user data whichis stored in the responsible register node CDNR2. This is indicated inFIG. 1 by the arrow 5, the arrow 5 a illustrating the movement of theterminal UE from the region B into the region A.

The dynamic usage scheme:

The dynamic use of the network register DNR according to the inventionwill be explained in the following text with reference to FIG. 2. FIG. 2illustrates only one localization node DNLR 2, which is not associatedwith any region and which is also not associated with any data nodeDNDR. In the case of an actual telecommunications network T, there mayalso be a plurality of such localization nodes DNLR2.

As soon as a user activates his mobile terminal UE, it is registeredwithin the telecommunications network T under provision of itsidentifier. This is represented in FIG. 2 by the arrow 0, in which case,by way of example, the terminal is located in region B, which isassociated with a data node DNDR1. This data node DNDR1, which detectsthe new user, produces a new entry in its database with all thenetwork-related user data for this specific terminal UE determinedduring the registration process. In addition, this data node DNDR1 usesthe identifier associated with the terminal UE to calculate a hashvalue, stores it in association with the user data in its database andtransmits the information to the localization node DNLR1 that he, thedata node DNDR1 of the region B, is responsible for the user terminal UEand that he has stored the network-related user data of the terminal UE.To do this, the data node DNDR1 transmits its address within thepeer-to-peer network N to the localization node DNLR1. This isillustrated by the arrow 1. The localization node DNLR1 then stores theaddress associated with the hash value of the identifier of the terminalin its database.

After registration, the data node DNDR1 of the region B is responsiblefor management of the user data. This register node DNDR1 has all theuser data of the specific terminal UE, such as the registration statusand location and/or the network availability and network coverage withinthe immediate vicinity of the terminal UE. That register node DNLR1which is responsible for the hash value of the identifier of theterminal UE, in this case the register node for the region D, incontrast, has an entry in its hash table that the data node DNDR1 of theregion B is managing the user data for the terminal UE.

If an external system makes a request EQ or an internal system makes acorresponding request IQ for specific user data of the terminal UE, acorresponding request is sent to a localization node DNLR2, see thearrow 2, or to a data node DNDR2, see the arrow 2 a. The process will beexplained further in the following text starting from the localizationnode DNLR2. However, it can be applied analogously on the basis of thedata node DNDR2. The localization node DNLR2 receives the externalrequest EQ and calculates a hash value relating to the identifier of theterminal UE whose user data has been requested. As soon as thelocalization node DNLR2 has this hash value, it makes a request to thatlocalization node, here DNLR1, which is responsible for the hash valueof the terminal UE, requesting the address of that data node DNDR1 whichis in turn currently responsible for the management of the requesteduser data. This is illustrated by the arrow 3.

The localization node DNLR1, which is responsible for the hash value,receives the request and returns the address of that data node DNDR1within the peer-to-peer network N which is currently responsible for themanagement of the network related user data of the terminal UE. This isillustrated by the arrow 4 in FIG. 2.

As soon as the requesting localization node DNLR2 knows where it canobtain the requested user data, it sends a request for the user data tothe data node DNDR′ being currently responsible for the managementthereof, see the arrow 5. This data node DNDR1 then returns therequested user data to the requested localization node DNLR2, see thearrow 6. As soon as the user moves with his mobile terminal UE from theoriginal region to a new region A, see arrow 7, it is necessary totransmit his network-related user data to a new data node, that is tosay to the data node DNDR which is responsible for the new region A. Atthe same time as this data transmission, it is necessary to update theaddress information in the localization node DNLR1 which is responsiblefor the localization of the user data and the data node DNDF holdingthis data. This is illustrated by the arrow 8 in FIG. 2.

The described mechanism ensures that, when a request is made forspecific use data, the information as to where the user data iscurrently stored and the information associated with it as to where themobile terminal UE of the user is currently located or was most recentlylocated is always stored in the same localization node DNLR1. Incontrast, the network-related user data may be located in a changingform in any given data node DNDR in the peer-to-peer network N,depending on the region A, B, C, D, E in which the terminal UE iscurrently located. In consequence, the user data can migrate between thedata node DNDR in the network N in the described dynamic usage scheme.

1. A method for operating a telecommunications network for mobiletelecommunication, having a network register in which identifier ofmobile terminals and network related user data of the terminals arestored, wherein the network register is formed from a peer-to-peernetwork having a multiplicity of decentralized register nodes which arenetworked with one another and are each associated with a geographicregion, and wherein hash tables are held in the register nodes, in whichhash tables the identifiers of the terminals are stored as hash valuesand the user data is stored associated with these hash values, whereinthe peer-to-peer network has at least a first register node associatedwith a geographic region at which first register node a mobile terminalcan register for communication via the telecommunications network, and asecond register node, which is permanently assigned to the terminal andis associated with a geographic region, wherein a hash table is held inthe second register node, in which hash table the identifier associatedwith the terminal is stored as a hash value determined by means of apredetermined hash function, the terminal registers with the firstregister node by transmitting the identifier, when it is located in thefirst region, the first register node determines network-related userdata of the mobile terminal on registration, and determines the hashvalue for that identifier by means of the predetermined hash function,the first register node uses the hash value to determine the secondregister node, and either transmits the network-related user data tothis second register node or itself stores this user data in its hashtable together with the hash value and transmits only its own address inthe network to the second register node, and wherein the network-relateduser data or the address of the first register node is stored,associated with the hash value, in the hash table of the second registernode.
 2. The method as claimed in claim wherein a request of a systemfor the current network-related user data of the terminal is made to athird register node by transmitting the identifier associated with thisterminal, the third register node determines the hash value of theidentifier by means of the hash function, uses this hash value todetermine the second register node assigned to the terminal, andrequests the information which is associated with this hash value in thehash table of the second register node.
 3. The method as claimed inclaim 2, wherein, if the information is the network-related user data,this is transmitted to the requesting system.
 4. The method as claimedin claim 2, wherein, if the information is an address of a furtherregister node, the network-related user data are requested at thisregister node and, after receipt, is transmitted to the requestingsystem.
 5. The method as claimed in claim 1, wherein, when the terminalmoves into a different region, the terminal registers with the registernode which is responsible for this region and transmits the identifier,this register node determines current network-related user data of themobile terminal on registration, and determines a hash value for theidentifier, by means of the predetermined hash function, and in that iteither stores this hash value together with the current network-relateduser data in a hash table held in it, uses the hash value to determinethe second register node which is assigned to that terminal andtransmits its address to this second register node, which then storesthe address, associated with the hash value, in its hash table, or inthat it uses the hash value to determine the second register nodeassigned to that terminal and transmits the network-related user data tothis second register node, which then stores the user data, associatedwith the hash value, in its hash table.
 6. The method as claimed inclaim 1, wherein the network-specific user data comprises theregistration state of the terminal, its location in a specificgeographic region, and/or information relating to the availability andtechnology of access points to the telecommunications network within theregion.
 7. A telecommunications network for mobile telecommunication forcarrying out the method as claimed in claim 1, having a network registerin which identifiers of mobile terminals and network-related user dataof the terminals are stored, the network register being formed from apeer-to-peer network with a multiplicity of decentralized register nodeswhich are networked with one another and are each associated with onegeographic region, wherein hash tables are held to in the registernodes, in which hash tables the identifiers of the terminals can bestored as hash values and the user data is stored associated with thesehash values, wherein the peer-to-peer network comprises at least: afirst register node which is associated with a geographic region and atwhich a mobile terminal can register for communication via thecommunication network, and a second register node, which is permanentlyassigned to the terminal and is associated with a geographic region,wherein a hash table is held in the second register node, in which hashtable an identifier associated with the terminal is stored as a hashvalue determined by means of a predetermined hash function, the firstregister node is configured in that the terminal can register with it bytransmitting the identifier, when it is located in the first region, andis configured to determine network-related user data of the mobileterminal on registration, and to determine a hash value for theidentifier by means of the predetermined hash function, and wherein thefirst register node is further configured to determine the secondregister node from the hash value and either to transmit thenetwork-related user data to this second register node, or to store thisuser data itself in its hash table together with the hash value, and totransmit only its own address in the network to the second registernode, and the second register node is configured to store thenetwork-related data or the address of the first register node,associated with the hash value, in its hash table.
 8. Thetelecommunications network as claimed in claim 7, wherein a registernode is formed either by a data node and/or by a localization node, orby a node combined from a data node and a localization node.
 9. Thetelecommunications network as claimed in claim 8, wherein each region isassociated either with a data node and a localization node, or with acombined node.
 10. The telecommunications network as claimed in claim 8,wherein the user data associated with a hash value are stored in thedata node, and the address, associated with a hash value, of that datanode which holds the user data associated with the hash value, is storedin a localization node.
 11. The telecommunications network as claimed inclaim 7, wherein one or more or all the register nodes is or arearranged within network elements.
 12. The telecommunications network asclaimed in claim 7, wherein a specific register node or all of theregister nodes is or are configured to receive a request of a system fornetwork-related user data of a specific terminal, and to carry out asearch for this user data within the network.